September 2014 Issue

A summary of this month's contents.

Build an AM Radio

An AM (amplitude-modulation/ medium wave) is a classic must-do project for the electronics hobbyist. There is nothing quite like experiencing the thrill of constructing your first radio project and then switching it on for the first time to listen to a radio station broadcast!

Our AM Radio can be built in two forms – a shirt-pocket size compact radio or a retro-style mantel radio in a wooden cabinet. Uses a classic radio integrated circuit and mono audio amplifier. Just the thing for a father-and-son project!

LED Ladybird

This l.e.d. novelty is a vibrant, eye-catching electronic brooch or ornament that uses high-brightness l.e.d.s to produce an attractive display. Use as a headband, earring, badge or pendant.

The project is self-contained with a 3V lithium battery and pushbutton on-off. PIC-powered with free source code downloadable from our Library. View a video.

SMD components – good soldering skills are necessary.

Coins cells and button batteries can be highly dangerous if swallowed. Keep coin cells and button batteries away from babies and young children. More information...

Lifesaver for Lithium or SLA batteries

An essential device for protecting many types of rechargeable battery from total discharge. It cuts off power before the voltage reaches the ‘danger zone’ thereby preventing the battery from being irreversibly damaged.

Due to its exceptionally low ON-resistance and microamp current consumption it has no noticeable effect on available power or battery life. Its miniature size will fit into most battery compartments and it is suitable for 6V-24V sealed lead-acid (SLA) batteries, Lithium-Ion (Li-ion) and Lithium-Polymer (LiPo) batteries. Optional warning buzzer/ LED.

SMD components – good soldering skills are necessary.

‘Do Not Disturb’ Phone Timer

Take control of your phone again with this phone timer project! It is intended to give you some peace and quiet by preventing the phone from ringing at inconvenient moments, such as mealtimes or if watching a movie on TV. It does this by fooling the phone system into believing that the line is engaged, and hence the phone does not ring at all.

It automatically “reconnects” the phone after a time period has elapsed. Features five time settings from 15 to 120 minutes, time set / remaining indications, easy push button timer setting and cancel button. Entirely self-powered from the phone line itself. PIC-powered design with free source code downloadable from our Library.

Make Your Own PCBs (1)

First part in a key series bringing readers right up to date with modern hobbyist PCB production techniques. In Part One, a number of popular PCB design packages are compared and a clear winner is identified!